This PR decomposes `fabro run` into three composable primitives —
`create`, `start`, and `attach` — following the Docker-style lifecycle
model. Previously, `fabro run` performed everything in a single
monolithic function, and `--detach` was implemented by reconstructing
CLI argv to spawn a child process, which was brittle and hard to extend.
The new architecture cleanly separates concerns: `fabro create`
allocates the run directory and persists a `RunSpec` struct to
`spec.json`; `fabro start` spawns a detached `_run_engine` process (a
hidden internal command that reads `spec.json`) via `setsid`; and `fabro
attach` tails `progress.jsonl` with live rendering and handles
file-based interview IPC. `fabro run` is now a composition of these
three primitives, and `fabro run --detach` simply skips the attach step.
The main rendering work lives in a new `handle_json_line()` method on
`ProgressUI` that parses JSONL envelopes and dispatches to the same
internal rendering methods already used by the in-process event handler.
This preserves 100% rendering fidelity without duplicating
spinner/stage/tool-call logic — the attach loop just feeds file lines
into the same code paths. File-based interview IPC is handled in the
attach loop itself: it watches for `interview_request.json`, prompts the
user via `ConsoleInterviewer`, and writes `interview_response.json` back
for the engine to consume. The `hide_bars`/`show_bars` methods
previously private to `ProgressAwareInterviewer` are promoted to public
methods on `ProgressUI` and reused in both the attach loop and the
existing in-process interviewer.
The old `detach_run()` function in `main.rs`, which reconstructed argv
by string-scanning `std::env::args()`, is deleted entirely and replaced
by the `create` + `start` composition. New tests cover the
`handle_json_line` dispatch paths (stage started/completed, tool calls,
retro events, invalid input) and the CLI argument parsing for the new
command variants.
### Fabro Details
<details>
<summary>Ran 9 stages in 30m 55s for $8.55</summary>
| Stage | Duration | Cost | Retries |
|---|---|---|---|
| start | 0s | – | 0 |
| toolchain | 0s | – | 0 |
| preflight_compile | 1m 11s | – | 0 |
| preflight_lint | 12s | – | 0 |
| implement | 18m 15s | $5.28 | 0 |
| simplify_opus | 10m 31s | $3.27 | 0 |
| simplify_gpt | 0s | – | 0 |
| verify | 17s | – | 0 |
| fmt | 1s | – | 0 |
| **Total** | **30m 55s** | **$8.55** | **0** |
</details>
<details>
<summary>Ran <code>ImplementAndSimplify.fabro</code> (12 nodes and 15
edges)</summary>
```dot
digraph ImplementAndSimplify {
graph [
goal="Implement and simplify",
model_stylesheet="
* { backend: api; model: claude-opus-4-6;}
"
]
rankdir=LR
start [shape=Mdiamond, label="Start"]
exit [shape=Msquare, label="Exit"]
toolchain [label="Toolchain", shape=parallelogram, script="command -v cargo >/dev/null || { curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && sudo ln -sf $HOME/.cargo/bin/* /usr/local/bin/; }; cargo --version 2>&1", max_retries=0]
preflight_compile [label="Preflight Compile", shape=parallelogram, script="cargo check -q --workspace 2>&1", max_retries=0]
preflight_lint [label="Preflight Lint", shape=parallelogram, script="cargo clippy -q --workspace -- -D warnings 2>&1", max_retries=0]
fix_lints [label="Fix Lints", prompt="The preflight lint step failed. Read the build output from context and fix all clippy lint warnings.", max_visits=3]
implement [label="Implement", prompt="Read the plan file referenced in the goal and implement every step. Make all the code changes described in the plan. Use red/green TDD."]
simplify_opus [label="Simplify (Opus)", prompt="@prompts/simplify.md"]
simplify_gpt [label="Simplify (GPT-54)", prompt="@prompts/simplify.md", model="gpt-54"]
verify [label="Verify", shape=parallelogram, script="cargo clippy -q --workspace -- -D warnings 2>&1 && cargo nextest run --cargo-quiet --workspace --status-level fail 2>&1", goal_gate=true, retry_target="fixup"]
fixup [label="Fixup", prompt="The verify step failed. Read the build output from context and fix all clippy lint warnings and test failures.", max_visits=3]
fmt [label="Format", shape=parallelogram, script="cargo fmt --all 2>&1", max_retries=0]
start -> toolchain
toolchain -> preflight_compile [condition="outcome=success"]
toolchain -> exit
preflight_compile -> preflight_lint [condition="outcome=success"]
preflight_compile -> exit
preflight_lint -> implement [condition="outcome=success"]
preflight_lint -> fix_lints
fix_lints -> preflight_lint
implement -> simplify_opus -> simplify_gpt -> verify
verify -> fmt [condition="outcome=success"]
verify -> fixup
fixup -> verify
fmt -> exit
}
```
</details>
⚒️ Generated with [Fabro](https://fabro.sh)
---------
Co-authored-by: Fabro <noreply@fabro.sh>
Co-authored-by: Bryan Helmkamp <bryan@brynary.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Pre-generates a ULID in the parent, passes it to the child via hidden
`--run-id` arg, prints the ULID to stdout, and exits immediately.
Child stdout/stderr go to `{run_dir}/detach.log`. Uses `setsid()` on
unix to detach from the controlling terminal. Existing `fabro ps` and
`fabro logs` work with no changes since `run.pid` and `conclusion.json`
are written by the child as usual.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Rename 79 workflow files from .dot to .fabro extension across
fabro/workflows/, test/, test/docs/, and files-internal/demo/.
Update TOML configs, Rust production code, test code, and shell
scripts. Backward compat tests in test/attractor/ are unchanged.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- doctor_no_color test: add --dry-run flag to skip live network probes (11s -> <1s)
- retry tests: set retry_policy=linear for 500ms delay instead of 5s default backoff
- cli_backend tests: make poll_interval configurable on AgentCliBackend, use 10ms in tests
- doctor TOML fixtures: remove status.code=1 now that dry-run doctor exits 0
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
